In situations wherein several antennas are disposed vertically above each other on a common mast support and the antennas are required to rotate about the center line of the mast in order to eliminate blockage of microwave energy by the mast, it is necessary to couple a stationary transmission line fixed to the mast to the rotating antenna assembly.
The problem of coupling a relatively stationary microwave transmission line section to a transmission line section rotating relative thereto may create restrictions in power and bandwidth and may result in periodic variations in power (i.e., introduces "wow") due to the relative rotation. These problems may arise in a rotating antenna feed system.